62m on an island of coal, surrounded by fish

As the world's population nears 7bn, Channel 4 News asks: what are the benefits to the UK's 62m inhabitants of living on a densely populated group of islands off the European mainland?

The UK is by no means the most crowded country in the world. It ranks 53rd in one table of population density, three places ahead of Germany and nine places ahead of Italy.

Nor does there appear to be any obvious correlation between population density and economic success. Hong Kong, Singapore and Monaco are among the most crowded places on earth, yet they are all flourishing economically.

So what benefits accrue to the United Kingdom by being the size that it is, with the population that it has, in the second decade of the 21st century?

"Defining an optimum population is an appealing concept," says David Coleman, Professor of Demographics at Oxford University, "but it is difficult to nail down scientifically because different criteria lead to different conclusions."

That is a view shared by Jakub Bijak, demographer and statistician at the University of Southampton.

"I would be very wary of saying anything about the population being a direct cause of any advantage or disadvantage to the UK."

Different from the rest

What is clear is that a country with more than 60m inhabitants will have a bigger economic clout compared to, say, a country with six million.

Bear in mind also that there are wide fluctuations in population density across the UK, and that these bring different benefits. Housing tends to be more expensive in urban areas, but travelling becomes both easier and more crowded.

"It's worth remembering that the south east of England is different from the rest," Professor Mike Murphy of the London School of Economics told Channel 4 News.

"Scotland, by contrast, is low density and is keen to encourage immigration, while the rest of the UK is less enthusiastic. There's a perception that density of population is more of a problem in England."

Put another way, if Scotland and Wales were to secede from the UK, England would become Europe's most densely crowded region - possibly prompting a wave of emigration from these shores.

ONS predictions are in any case that the United Kingdom's population will have swollen to 77m by 2050 and to 85m by the 2080s.

"That's a huge time in demography, but it's what would happen if mortality kept increasing, fertility maintained at 1.84, and net immigration was 180,000 per year," says Professor Coleman. "In the last few years, though, immigration has been substantially higher than that."

Jakub Bijak stresses that the ONS projections come with big caveats, suggesting that a plausible time-frame for population predictions should be no more than 20-30 years - "beyond that it's an extrapolation of past trends".

Coal and fish

And what, if any, have been the advantages of being, as Labour politician Aneurin Bevan famously described the UK, "an island made mainly of coal and surrounded by fish"?

"If you look at it over the long term, the country's been defended, there's been less warfare, and you've had a resource like fish," says Mike Murphy.

An island mentality may also explain the United Kingdom's reluctance to become part of the Schengen area of the EU, where there are no border controls between countries. Only the UK and Ireland have yet to implement the agreement.

Unlike most of its European partners, UK has also benefited from North Sea oil, while the discovery of North Sea gas prompted energy suppliers to switch towards electricity generation using natural gas in the 1990s.

The downside of the "dash for gas", though, may have been that the country focused on gas as its main energy source, to the detriment of developing more sustainable sources of energy.